Psychological distress, BMI have near-zero association in adults

BMI appeared “weakly correlated” with psychological distress, according to study results published in Journal of Psychiatric Research.

“The co-occurrence of obesity and psychological distress has been well described, especially for depressive and anxiety disorders,” Bruno S. Scarpato, MD, of Federal University of Sao Paulo’s department of psychiatry, and colleagues wrote. “However, the current literature reports controversial bi-directional findings, inconsistent evidence regarding the magnitudes of these correlations, and heterogeneous interrelated trajectories that differ according to sociodemographic moderators, such as race and sex, and across age groups.”

The researchers analyzed BMI data, self-reported psychological distress through the Malaise Inventory (MI) and self-reported depressive symptoms through the Center for Epidemiological Studies Depression Scale (CES-D) to determine the relationship between BMI and psychological distress.

There were three cohorts: the Coronary Artery Risk Development in Young Adults (CARDIA) in the U.S. and the National Child Development Study (NCDS) and the British Cohort Study (BCS) in Britain. CARDIA used the CES-D in its evaluation of adults in nine waves of data collection between 1985 and 2016 for cardiovascular risk factors and disease evolution. The BCS began in 1970 as part of the NCDS, which began in 1958. Both British birth cohorts used MI data.

Depressive symptoms in the CARDIA cohort had a small correlation with age, with a decrease in symptoms from age 30 to 40 years and a slight increase from 45 to 50 years. Similarly, MI scores for men in the NCDS and BCS showed a decrease in psychological distress from ages 23 to 33 years and a slight increase from ages 34 to 50 years. Patients born more recently more frequently had higher psychological distress scores.

Across all cohorts, BMI increased over time and with age, with participants considered almost overweight on average by the end of each study period, Scarpato and colleagues wrote.

BMI and psychological distress were heavily dependent on long-standing interpersonal traits. However, long-term BMI only had a small association with long-term psychological distress among women, who had a near-zero correlation between higher BMI in the NCDS and CARDIA with more psychological distress and depressive symptoms, respectively. There was no observed association in men.

Occasion-specific effects for BMI and psychological distress were more influential at later time points, though those for BMI had stronger autoregressive effects.

“These strong trait influences, differential autoregressive effects, taken together with good model fit indices, justify the use of the [random-intercept cross-lagged panel model (RI-CLPM)] to disentangle these important sources of information before considering longitudinal dynamics between these measures,” Scarpato and colleagues wrote.

Moving forward, the researchers suggested studies examine heterogeneity in the RI-CLPM, as well as the association between depressive symptoms and BMI in subgroups.